It is well accepted in scientific circles that there is a correlation between the electroencephalographic wave rhythms exhibited by the brain of a human and the state of consciousness of that being. Rhythms customarily found in the normal human adult when he is relaxed and his eyes closed have a pulse frequency in the seven-fourteen Hz. range and have come to be identified as "alpha" rhythms. Similarly, when a person is aroused and anxious, the rhythms exhibited fall in the 14-28 Hz. range and are known as "beta" rhythms. A normal person in sleep exhibits "delta" rhythms in the 1.75-3.5 Hz. ranqe. Other brain wave rhythms which have been identified by researchers as being associated with various normal and abnormal states of consciousness are: "theta", 3.5-7.0 Hz. and "gamma", 28-56 Hz. Research by the applicant has led to the identification and naming of three additional rhythms, namely: "omega", 0.875-1.75 Hz.; "epsilon", 56-112 Hz.; and "zeta", 112-224 Hz.
Researchers have devised a variety of systems for stimulating the brain to exhibit specific brain wave rhythms and thereby alter the state of consciousness of the individual subject. Most of these efforts have been aimed at inducing an alpha, or relaxed, brain wave rhythm or a delta, or sleep, brain wave rhythm.
E.W. Ballentine and B.C. Gindes, in their U.S. Pat. No. 3,762,396, granted Oct. 2, 1973, for "Method and Apparatus for Inducing Sleep by Applying Electrical Pulses to Plural Portions of the Head", disclose a system for inducing sleep, treating psychosomatic disorders, and aiding the induction of hypnosis. With this system, the patient is subjected to three stimuli. The first stimulus is electrical current pulses having a frequency of 8-10 CPS applied by electrodes to the back of the head. A second stimulus of electrical current pulses having a frequency four times the frequency of the first stimulus is applied to the optic nerve through electrodes on the forehead. The third stimulus is a sound signal produced by the first stimulus and applied to the patient via sound attenuating chambers in order to isolate the patient from a noisy environment.
U.S. Pat. No. 3,576,185 was granted Apr. 27, 1971, to H. Shulz for "Sleep-Inducing Method and Arrangement Using Modulated Sound and Light". This patent describes an apparatus and a method for inducing sleep by directing at the subject two sound signals in the range of 40-80 Hz., free of overtones and amplitude modulated between the perceivable minimum and a perceivable maximum. The two signals differ in frequency by approximately 0.5-2 Hz. Optical stimuli may also be used.
K. Masaki in his U.S. Pat. No. 4,834,701, granted May 30, 1989, for "Apparatus for Inducing Frequency Reduction in Brain Wave" states his objective to be the reduction of beta-rhythm into alpha-rhythm as well as to retain alpha-rhythm. The subject is subjected to two sound signals which are each higher in frequency than 4-16 Hz. But are different and produce a beat signal which is within the 4-16 Hz. range. It is represented that the subject exhibits improve ability in learning, researching and inventing.
B.C. Gindes also teamed with B.C. Meland to obtain U.S. Pat. No. 4,227,516, granted Oct. 14, 1980, for "Apparatus for Electrophysiological Stimulation". This patent discloses apparatus for stimulating the effects of brain wave activity in one of the delta, theta, alpha, and beta brain wave frequency ranges. A first wave is generated in a frequency range above the brain wave ranges. This first wave is then modulated by a second wave having a frequency within one of the brain wave frequencies. The modulated first waves are applied to the subject by means of electrodes on the forehead. The second wave may also be applied by sound through headphones. A third wave in a range 150-600 Hz. may be modulated by the second wave and the modulated tone that is produced applied to headphones worn by the subject. The system is represented as being able to, among other things, induce sleep, induce a hypnotic state, produce heightened awareness and increase the ability of a person to concentrate.
Each of the systems disclosed in these prior patents require that fairly complex apparatus be directly associated with the subject. And the systems of the two Gindes, et.al. patents hamper useful activity of the subject by the requirement that the subject be attached to electrodes and earphones.
There continues to be a need for a system for inducing brain wave rhythms which is inexpensive and easy to use from the subject's point of view.